Question

A student thinks the sum of 4.3 and 8.4 is 12.7 because 4+8= 12 and 3+4=7. The student then adds 3.7 and 2.6 and gets 5.13 because 3+2=5 and 6+7=12 Identify the mistake in the students procedure and explain why the procedure wont always work

Answer 1

Student needs to learn the position value of decimal numbers, and that a carry should not shift the digits to the right.